Antimicrobial and iNOS inhibitory activities of the endophytic fungi isolated from the mangrove plant Acanthus ilicifolius var. xiamenensis

Abstract

BackgroundAcanthus ilicifolius var. xiamenensis (Acanthaceae) is an old world mangrove species and has long been used as a folk remedy for treating various ailments in traditional medicine. The nature source of A. ilicifolius var. xiamenensis is now in short supply because of the urban development and habitat destruction. To better utilize this resource, biodiversity and bioactivity of endophytic fungi isolated from A. ilicifolius var. xiamenensis were investigated.ResultsA total of 168 fungal isolates were cultured from leaves and stems of the mangrove plant collected in January (winter) and July (summer) 2014 at Kinmen County, Taiwan. Spent culture extract of 28 isolates were found to have bioactivities against one of the following pathogenic microorganisms: the bacteria Bacillus subtilis, Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) and the fungi Candida albicans and Cryptococcus neoformans. These positive extracts were mostly active against the Gram-positive bacteria and C. albicans. Corynespora cassiicola NTOU4889 and Xylaria sp. NTOU4900 inhibited growth of all 3 test bacteria whereas Phellinus noxius NTOU4917 inhibited both test fungi. A further anti-inflammatory study of culture extracts of these 28 isolates revealed that extracts with a high iNOS inhibition caused a low viability of cells, and those with a low iNOS inhibition had a high cell viability. Three extracts showed low cytotoxicity (i.e. > 100% cell viability) and high iNOS inhibition (< 15% of NO production) of cells and they were Phoma sp. 2 NTOU4338, Nodulisporium sp. NTOU4868 and Guignardia sp. NTOU4871.ConclusionThese results indicate that the endophytic fungi associated with A. ilicifolius var. xiamenensis can be a potential source of novel natural active substance.

Antibiotics Development and the Potentials of Marine-Derived Compounds to Stem the Tide of Multidrug-Resistant Pathogenic Bacteria, Fungi, and Protozoa

“…ZZ446, in solid medium with sea salt, produced rare diketopiperazine glycosides (Maculosin and maculosin-O-a-L-rhamno-pyranoside (1, 2)), which inhibited MRSA (MIC, 37.0 µg/mL) [32]. However, previously, this bacterium in liquid medium with sea salt, produced streptopyrazinones A-D (1-4), N-acetyl-L-isoleucine-L-leucinamide (5), diketopiperazines (6)(7)(8)(9)(10)(11), and alkaloid (12). Only the new compounds (1-5) were tested and they showed antimicrobial activity against pathogens, including MRSA ATCC 43300 at (MIC, 58.0-65.0 µg/mL) [33].…”

“…There are more than two hundred thousand described species of algae and invertebrates in the ocean, and representatives of every phylum (marine organisms are exclusively the twelve phyla) are found in the sea. Only a small percentage of the total number of species living in these habitats have been discovered and described [11,12]. The bacteria in the oceanic subsurface are believed to be up to ten percent of the total living biomass carbon in the biosphere.…”

“…Di Zhang and his group isolated Streptomyces sp. ZZ741 (China) that produced new streptoglutarimides A−J (1−10) as well as a known streptovitacin A (11). Some of these compounds displayed antiproliferative properties, and antimicrobial activity against test pathogens which includes MRSA (MIC, 8−12 µg/mL) [40].…”

“…An aromatic polyketides-producing fungus, Penicillium sp. SCSIO 06720 (Indian Ocean), produced 5-[2-hydroxypropane-1-yl]-2,6-dimethlben-zene-1,3-diol (1) and coniochaetone L (2), together with another 19 known compounds (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Only compound 16 exhibited moderate antibacterial activities, including against MRSA-shh-1 at MIC of 46.9 ± 29.7 µg/mL [81].…”

“…The extracts from rice fermentation medium of Aspergillus sp. strain SCSIO06786 led to the isolation and identification of fourteen compounds, which include new compounds such as a quinoline alkaloid (1), two bisabolane-type sesquiterpene derivatives (2 and 3), and a new natural product (4), along with another ten known compounds (5)(6)(7)(8)(9)(10)(11)(12)(13)(14). Only compound 11-13 exhibited antibacterial activity against the test pathogens, including MRSA at MIC values of 3.13, 12.5, and 12.5 µg/mL [84].…”